Abstract: In order to understand the distribution and influencing factors of PM_2.5 and PM₁₀ concentration in different neighbourhoods and road environments, the data of PM_2.5 and PM₁₀ concentration and water film height collected from different functional blocks during July 14 ^th to July 16 ^th, 2016 were analyzed. The result showed that the rainfall helped decrease the concentration of PM_2.5 in the ambient environment, and there was a negative correlation between the water film height and particulate matter concentration. Fine particle pollutants predominated in the particulates of residential areas and Hongqiao business district. In addition, due to the impact of the construction sites and road dust, there were serious coarse particle pollutants somewhere in Hongqiao business district and industrial areas. The pollution in Lujiazui business district was slight because the diffusion condition was fine and there were no serious polluting blocks. According to the measurement results, not all the viaducts will deteriorate the air quality in the street canyons, and the viaducts will have little effect on the diffusion of pollutants in the street canyon if the structure of the street canyon is reasonable.